ardly a day goes by without an expert proposing more foreign aid or support for education as a cure for terrorism. There are compelling reasons for improving the living standards and education of people in developing countries, but is reducing terrorism one of them?

Available evidence from a close cousin to terrorism — violent crimes against religious, racial or ethnic groups — yields surprisingly little support for a connection between material well-being or education and hate crimes.

Until recently, social scientists thought economic deprivation was a crucial determinant of such crimes. The logic is obvious: the most disadvantaged have the least to lose (especially in suicide attacks), and minority groups are a convenient scapegoat in times of trouble.

The empirical support stemmed mainly from historical evidence on lynchings of blacks in the South. In 1940, the psychologists Carl Hovland and Robert Sears reported a correlation between the value of an acre of cotton and the number of lynchings, using data from 1882 to 1930. As economic conditions improved, lynchings fell.

But a careful study by Donald Green, Jack Glaser and Andrew Rich of Yale, published in The Journal of Personality and Social Psychology in 1998, showed that this correlation vanished when pre-existing trends were taken into account. That is, apart from the long-term tendency for the number of lynchings to decline and the economy to grow, lynchings were unrelated to year-to- year economic changes. More important, when they examined additional years of data, they discovered that lynchings did not rise during the Great Depression.

The evidence of a connection in contemporary events is also elusive. Professors Green, Glaser and Rich studied the incidence of hate crimes against blacks, Jews, Asians and gay men and lesbians in New York City each month from 1987 to 1995. They found that the incidence of such crimes was unrelated to the city's unemployment rate.

The United States does not appear to be unique. Germany experienced a rash of organized violence against foreigners in the early 1990's. Unemployment was high, particularly in the former East Germany. Yet in a study published in The Journal of Human Resources, Jörn-Steffen Pischke and I found no relationship between the unemployment rate and the incidence of ethnic violence across counties in Germany. Likewise, average education was unrelated to the amount of violence against foreigners.

Neither cyclical downturns nor longer-term disparities in living standards appear to be correlated with a wide range of hate crimes.

This is not proof of the absence of a causal relationship, but any causal effect of economic conditions is likely to be complex, indirect and weak. If there was a direct effect, one would expect hate crimes to rise during periods of economic hardship.

But do the findings from these studies apply to terrorism, particularly for the poverty-stricken and poorly educated populations in the Middle East? Hate crimes could be spawned by different conditions from those that are responsible for politically motivated attacks.

The fragmentary evidence on terrorists, however, suggests that the common stereotype that they come from the ranks of the most uneducated and economically deprived is a myth.

From 1996 to 1999, Nasra Hassan, a United Nations relief worker, interviewed nearly 250 people involved in suicide attacks, including failed bombers, families of deceased bombers and trainers. Her conclusion, as reported in The New Yorker: "None of them were uneducated, desperately poor, simple-minded or depressed."

Professor Ariel (news/quote) Merari, director of the Political Violence Research Center at Tel Aviv University, concurred: "All information that I have also indicates that there is no connection between socioeconomic indicators and involvement in militant/terrorist activity in general and in suicide attacks in particular, at least as much as the Palestinian case is concerned."

The profile of the 19 terrorists who carried out the Sept. 11 attacks — many of whom were college-educated and from middle-class families — may not be so atypical after all.

Another fragment of evidence is that the average illiteracy rate of men in the seven countries the State Department designated as sponsors of terrorism (Cuba, Iran, Iraq, Libya, North Korea, Sudan and Syria) is 17 percent — about the same as the worldwide illiteracy rate. Ireland and Spain, which have struggled with terrorism for years, are neither poor nor neglectful of education.

The impact of education on international terrorism is undoubtedly complicated. Certainly, terrorists with global reach are likely to be drawn from the ranks of the educated and relatively well off, so they can blend into their new environs. Schools might be preaching hatred instead of peace and harmony, as Thomas L. Friedman has argued in The New York Times (news/quote).

A country's economic development may influence terrorism and political violence in another way: by affecting the likelihood of civil war.

A new study by James Fearon and David Laitin, political scientists at Stanford, finds that nations with a lower per-capita level of gross domestic product are more likely to undergo a civil war. In fact, economic development is a far more important predictor of civil wars than is whether a nation's population is fragmented along religious or ethnic lines. Mr. Fearon and Mr. Laitin highlight the role of "insurgency" as a cause of civil war: weak states are unable to suppress insurgents intent on waging a civil war. The governments in poor countries lack the means, skills and knowledge to thwart rebellions. In addition, they argue, it is easier for insurgents to recruit foot soldiers where poverty is high.

Why might economic development affect civil wars and terrorism differently? Mr. Fearon suggested: "You get terrorism when the state is strong and competent enough to prevent the initial attacks of would-be rebel leaders from escalating into a big civil war (e.g., Northern Ireland, the Basque region in Spain, the Red Brigade in Italy). Income, we argue, is a measure of such capabilities."

So a Marshall Plan to aid economic growth may lead to greater stability. Moreover, fostering development would alleviate much suffering, and promoting education would generate many benefits, including improved health, faster economic growth and participation of the disenfranchised in modern society. Alas, there is little ground for optimism that such worthy assistance would greatly reduce international terrorism.